BRPI0713078A2 - method and apparatus for producing ground malt extract - Google Patents

Abstract

METHOD AND APPARATUS FOR PRODUCING A GROUND MALE EXTRACT. One aspect of the invention relates to a method comprising: a) macerating starch containing particulate raw materials and optionally malted with water; (b) heating the ground malt and enzymatically hydrolyzing the starch; c) passing the heat-treated ground malt in a first sieve for separation into a fermentable ground malt extract and wet spent grain; d) transferring the wet spent grain optionally after said wet spent grain has been subjected to a washing and sieving operation to a first press and pressing said wet spent grain to remove water spent grain and additional fermentable ground malt extract. The present method offers the advantages of (i) being very robust, (ii) allowing the production of high density ground malt extracts, (iii) consuming very little electricity; and (iv) achieve high extraction yields. The invention also provides an apparatus for performing the above method.

Description

"METHOD AND APPARATUS FOR PRODUCING A GROUND MALT EXTRACT"

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method of producing a ground malt extract, especially a ground malt extract which is suitable for use in the production of a yeast fermented beverage such as beer. More particularly, the present invention provides a method comprising:

The. macerate starch-containing particulate raw materials and optionally malted with water;

B. heat the ground malt and enzymatically hydrolyze the starch;

ç. separate the heat-treated ground malt into ground malt extract and spent grain.

The invention also relates to an apparatus for performing such a method.

BACKGROUND OF THE INVENTION

A maceration method such as that described herein is disclosed in GB-B 879 470. More specifically, said English patent describes a continuous method for the production of beer wort wherein heat-treated ground malt is introduced into a first separator. sieve Worn grain that does not pass the first sieve separator falls into a first wash vessel where it is found and is mixed with a very diluted must from the sieve separation of a grain suspension from a second wash vessel. The mixed suspension in the first wash vessel overflows into a second sieve separator. Diluted mash passing through the second sieve separator is recirculated to the maceration step and spent grain not passing through the sieve falls into the second wash vessel where it is combined with a stream of water. The suspension in the second wash vessel overflows into a third sieve separator. The very diluted must passing through the sieve is pumped into the first wash vessel and the spent grain discharged from the sieve goes into disposal of spent grain.

The method described in the English patent comprises continuously subjecting the solids fraction to countercurrent extraction in a plurality of stages, each of which comprises re-mudding with a later stage scrubbing effluent and mechanically separating the coarse solids to produce a solid residue. coarse solids substantially exhausted completely. The examples of the English patent describe the results of three different production runs. Process must currents produced in these runs had a specific weight (S.G.) in the range of 1.04117 to 1.04484. These specific weights are equal to a density of about 10-11 degrees Plato (0P).

DE-B 516 547 describes an apparatus in which ground malt is separated into fermentable ground malt extract and wet spent grain by passing the ground malt through a sieve followed by pressing the wet spent grain thus obtained by means of a press piston. against a sieve to obtain dehydrated spent grain and additional fermentable ground malt extract.

DE-B 165 124 describes a process for continuous must production that employs a sequence of three press chambers. The first and third chambers contain a screw press that is mounted on a conically shaped cylinder. This cylinder is perforated or comprises a sieve to allow liquid to flow. The second chamber is used to spray the spent grain leaving the first chamber before it is transferred to the third chamber. Sprinkler water is used in the process in a counter current manner. In the process disclosed in the German patent, screening and pressing take place essentially simultaneously. US 3,157,583 discloses a process for the production of clarified malt extract in which ground malt passes through a vibrating screen to remove most of the fibrous material and bark, and wherein the fibrous material and removed bark is transferred to another vibrating screen where it is washed with sprinkling water.

SUMMARY OF THE INVENTION

The inventors have developed a novel process for producing a fermentable ground malt extract that offers the advantages of (i) being very robust, (ii) allowing the production of high density ground malt extracts, (iii) consuming very little energy. and (iv) achieve high extraction yields.

The present method is characterized in that it employs one or more sieve - press combinations to produce the fermentable ground malt extract. More particularly, the present method is characterized in that it comprises the following steps:

The. macerate starch-containing particulate raw materials and optionally malted with water;

B. heat the ground malt and enzymatically hydrolyze the

starch;

ç. passing the heat treated ground malt in a first sieve for separation into a fermentable ground malt extract and wet spent grain; and

d. transferring the wet spent grain, optionally after the wet spent grain has been subjected to a washing and screening operation, to a first press and pressing said wet spent grain to obtain dehydrated spent grain and additional fermentable ground malt extract.

One or more sieve-press combinations that are employed in the present method may conveniently be operated continuously. The sieves (or screens) can be operated at high production to achieve a first solid-liquid separation. Since the solids fraction retained in the sieves is typically much smaller than the permeate liquid fraction, the presses can be operated at a much lower output to remove virtually all liquid that is still contained in the solids fraction. The present method combines the ability of sieves to effectively separate low solids streams with the ability of presses to effectively separate high solids streams. Thus, the use of sieve press combinations in the present method offers the advantage of high production and high efficiency. DRAWINGS

Figure 1 is a diagram of an apparatus for continuously producing a high density ground malt extract using the method of the present invention, said apparatus employing two sieve-press combinations and a mixing vessel for producing the ground malt extract. .

Figure 2 is a diagram of an apparatus for continuously producing a high density ground malt extract, the apparatus comprising three sieve - press combinations and two mixing vessels.

Figure 3 is a diagram of an apparatus for the continuous production of a density algae ground malt extract which is quite identical to the apparatus shown in Figure 1, except that the first sieve-press combination comprises an extra sieve and a spray vessel. . DETAILED DESCRIPTION OF THE INVENTION

Accordingly, an aspect of the invention relates to a method comprising:

The. macerate starch-containing particulate raw materials and optionally malted with water;

B. heat the ground malt and enzymatically hydrolyze the starch; ç. passing the heat treated ground malt in a first sieve for separation into a fermentable ground malt extract and wet spent grain; and

d. transfer the wet spent grain, optionally after the wet spent grain has undergone a washing and drying operation.

sieving, for a first press and pressing said wet spent grain to obtain dehydrated spent grain and additional fermentable ground malt extract.

The term "macerate" as used herein refers to the mixture of starch-containing raw material, water and enzymes capable of hydrolyzing starch. The latter enzymes may be provided, for example, by malt or another enzyme source, for example, a commercially available enzyme preparation containing starch degrading enzymes, such as those found in malt, notably α-amylase, β-amylase. and / or glycoamylase. Preferably, the enzymes are employed in the present method in malt form.

It should be understood that, whenever reference is made to a first sieve, a second sieve, a third sieve, etc., such first, second or third sieve may actually comprise two or more sieving devices which together perform the separating action. solids and liquid based on particle size. These two or more screening devices may be operated in parallel and / or in series. For example, it may be advantageous to employ a sieve consisting of a stack of sieving devices, wherein the pore size of the sieving devices decreases downstream. Similarly, it may be advantageous to employ a sequence of presses, where the applied pressure increases in the downstream direction. It may also be advantageous to operate several screening or press devices in parallel, particularly if the process is operated continuously. When working in parallel well below the maximum production capacity, failure or shutdown of a separation device does not require interruption of the ground malt extraction process, meaning that the process can be operated uninterrupted for extended periods of time.

Just like the sieves and presses, also the mixing vessels employed in the present process can actually consist of two or more mixing devices which are operated in series or in parallel.

A particularly advantageous embodiment of the present process comprises the additional steps of:

and. transfer the dehydrated spent grain to a first mixing vessel and mix it with sprinkling water to produce a suspension;

f. passing the suspension through a second sieve to separate washed spent grain and wash water; and

g. transferring the washed spent grain to a second press and pressing said washed spent grain to obtain spent grain residue and resting water.

The use of an additional washing step according to this embodiment makes it possible to further reduce extract losses.

In another preferred embodiment, prior to being transferred to the first press, the wet spent grain is subjected to a washing and screening operation comprising:

• transfer the wet spent grain to a washing vessel and mix it with sprinkler water to produce a suspension;

• pass the suspension through an additional sieve for separation of wet spent grain and wash water.

This embodiment also offers the advantage that extract losses can be minimized very effectively.

Accordingly, a particularly preferred embodiment of the present invention relates to a method of producing a ground malt extract as defined hereinbefore, wherein the method comprises the additional steps of:

and. transfer the dehydrated spent grain to a first mixing vessel and mix it with sprinkling water to produce a suspension;

f. passing the suspension through a second sieve to separate washed spent grain and wash water; and

g. transfer the washed spent grain to a second press and press said washed spent grain to obtain spent grain residue and resting water,

and / or, wherein, before being transferred to the first press, the wet spent grain is subjected to a washing and sieving operation comprising:

• transfer the wet spent grain to a washing vessel and mix it with sprinkler water to produce a suspension;

• pass the suspension through an additional sieve for separating wet spent grain and wash water, and wherein at least a portion of the wash water and / or the rest water is recirculated to the maceration step a and / or combined with the heat treated ground malt before it passes the first sieve.

According to another particularly preferred embodiment of the invention, at least a portion of the wash water and / or rest water obtained from the sieves and / or presses is recirculated to the maceration step and / or combined with the treated ground malt. thermally before it passes the first sieve. The recirculation of wash and / or rest water offers the important advantage that it allows high extraction yields without the need to use large amounts of water. At the same time, recirculation makes it possible to achieve such high extraction yields while producing a high density ground malt extract. Particularly good results in terms of efficiency and yield can be achieved if both wash and rest water are completely recirculated, especially if they are recirculated to the maceration step a. Recirculation for the maceration step compared with recirculation for heat treated ground malt offers the advantage that starch hydrolysis can be achieved very efficiently without using large amounts of water and / or long residence times.

In the maceration step, in addition to the recirculated aqueous stream from the second sieve-press combination, also recirculated aqueous streams generated downstream of the brewery, for example from the yeast wash, may be employed.

Typically, in the present process, the total amount of recirculated wash water and rest water constitutes at least 80 wt%, preferably at least 90 wt% of the total amount of water employed in the maceration step a. More preferably, the wash and rest water of the second sieve-press combination provides all the maceration liquid that is used in the maceration step.

In another preferred embodiment, steps c. a g. of the present method are carried out continuously. Even more preferably, steps b. a g. and more preferably steps a. a g. are performed on a continuous basis. Because of its robustness, the present process is perfectly suited to be operated continuously for extended periods of time.

The present method may suitably employ any type of sieve capable of retaining a substantial fraction of the solids contained in the ground malt or spent grain suspension. Particularly suitable are vibrating screens. A particularly suitable type of vibrating screen is provided with free-moving elements which, under the influence of vibrations, can strike the underside of the screen. Such free-moving elements may suitably be in the form of spheres or rings. An important advantage of this type of arrangement is that it helps prevent clogging of the sieve pores. A suitable screening device is supplied by Allgaier Werke GmbH, Germany.

The pore size of the sieves employed in the present process is typically in the range of 20 μπι to 1 mm. Preferably, the pore size of the sieves is in the range of 20-300 μιη. More preferably, said pore size is in the range dd 32-200 μιη, above all preferably in the range 32-100 μιη. The present method can be operated using all types of presses. Preferably, the method employs presses that can be operated continuously. Particularly suitable for use in the present method are screw presses. A suitable screw press is supplied by Ponndorf Maschinenfabric GmbH, Germany, or van Tongeren- Kennemer Β. V. Beverwijk, The Netherlands.

According to a preferred embodiment, the presses are provided with a sieve by which additional fermentable ground malt extract is expressed and which retains the spent grain dehydrated. Typically, the pore size of the sieve is in the range of 20-800 μιη. Preferably, the pore size of the sieve is in the range of 20-300 μιη. More preferably, said pore size is in the range of 32-200 μιη, above all preferably in the range of 32-150 μηι.

The solids content of the dehydrated spent grain obtained from the first press typically is at least 18% by weight. Preferably, the solids content is at least 20 wt%, more preferably at least 25 wt%, even more preferably at least 30 wt%, and most preferably at least 35 wt%. In particular, if the present method employs a sequence of three or more sieve - press combinations, extract losses can be minimized very effectively. Accordingly, a preferred embodiment of the invention relates to a method as defined above, said method further comprising:

H. transferring the spent grain residue obtained from the second press to a second mixing vessel and mixing it with sprinkling water to produce a suspension;

i. passing the suspension through a third sieve to separate extracted spent grain and diluted wash water;

j. transferring the extracted spent grain to a third press and pressing said extracted spent grain to obtain exhausted spent grain residue and dilute resting water; and

k. recirculate at least a portion of the diluted wash water and / or dilute resting water to the first mixing vessel.

The extract loss observed in the method is typically less than 15 wt%. Extract losses of less than 10 wt%, or even less than 5 wt%, and more preferably less than 3 wt% can be achieved in the present method. Preferably, the latter efficiencies are realized by the whole must production process including both ground malt separation and sediment separation. The amount of extract loss in the production of a ground malt extract can conveniently be determined by measuring the extract concentration in the liquid phase of the grain spent by a standard method to determine must extract concentrations (e.g., measuring density by Anton Paar). Because of the absence of free liquid in the dehydrated spent grain, said spent grain is conveniently extracted with hot water, after which the spent spent grain is filtered off. Extract losses can be calculated from the extract level measured in the extraction liquid, taking into account the amount of water added.

In the present method, the density of the fermentable ground malt extract obtained from the first separator typically exceeds 150 P. The advantages of the present method are particularly pronounced where the density of the ground malt extract obtained from the first separator exceeds 180 P. More preferably the density of the ground malt extract exceeds 20 0P, even more preferably it exceeds 25 0P. In an especially preferred embodiment, the density of the ground malt extract obtained from the first separator exceeds 28 0P, more preferably exceeds 30 0P. These high densities can be achieved with minimal extract losses in the event that the fractions of liquid obtained from the sieves and presses are all recirculated in an upstream direction. In a particularly preferred embodiment, the present process does not produce any liquid waste stream, i.e. essentially all externally supplied water ends in the ground malt extract, more preferably essentially all of it ends in the fermented mash that is produced from the ground extract. ground malt.

It is well known in the brewing industry to produce a high density fermentable ground malt extract by incorporating a significant amount of together (eg syrup), especially after enzymatic hydrolysis of the starch contained in the ground malt. These adjuncts can provide high concentrations of fermentable sugars and, consequently, can be used to intensify the density of ground malt extract and must. In the present method, high densities can be achieved in ground malt extract and must without the addition of fermentable sugars after enzymatic hydrolysis of the starch contained in ground malt. Typically, less than 30 wt.%, Preferably less than 10 wt.% Of fermentable sugars in the ground malt extract and must are derived from fermentable sugars added after hydrolysis of the starch contained in the ground malt. More preferably, the ground malt extract and mash do not contain fermentable sugars derived from fermentable sugars added after hydrolysis of the starch contained in the ground malt.

It is also known to increase the density of evaporated ground malt or mash extracts. In the present process, preferably concentration by evaporation is not employed.

The present method is particularly suitable for producing a ground malt extract which can be used in the production of yeast-fermented malt beverages such as beer, ale, malt liquor, dark beer and lemonade beer mix, especially an alcoholic beer. or non alcoholic.

Accordingly, the present method preferably comprises the additional steps of:

converting the optionally hopped macerated extract into must by heating said ground malt extract at a temperature of at least 60 ° C for at least 15 minutes;

- remove organic volatiles from the hot must by reducing the pressure and / or by removing them with a gas or vapor. In a particularly preferred embodiment, the density of the ground malt extract is maintained at 150P or higher, preferably 180P or higher, more preferably at 20P or higher during these additional steps. Even more preferably said density is maintained at at least 25 0P, more preferably at least 30 P during these additional steps.

In the present process, the ground malt extract is preferably converted to wort by heating said ground malt at .75-150 ° C for 30 minutes to 4 hours, preferably for 30 minutes to 2 hours. The ground malt extract can conveniently be converted to must in a buffer flow reactor.

Organic volatiles are removed from the hot must by reducing the pressure and / or by removing them with gas or steam. This is preferably done in a counter current manner. More preferably, the organic volatiles are removed by removing hot must with an inert gas or steam on a column equipped with a screening plate geometry. Typically, the wort is kept at a temperature of 95-110 ° C when the organic volatiles are removed. The removal of volatiles may conveniently be accomplished within 10 minutes, preferably within 2 minutes.

Hot must obtained after removal of organic volatiles contains a suspension consisting roughly of proteins, protein-tannin complexes and hops, commonly referred to as hot sediment or breakage. The hot break or sediment is removed in a separator. Examples of suitable separators include centrifuges, decanters, hydrocyclones, sedimenters, sieves and membrane filters. Preferably, the separator is selected from the group consisting of decanters, settlers and disc-type centrifuges. More preferably, the separator used is a disk type centrifuge. Typically, the separator is operated at a theoretical capacity factor value of at least 1,000 m, preferably at least 2,500 m2 and more preferably at least 5,000 m at a must flow rate of 1 m / hour. Higher capacities can be proportionally adapted with separator flow and theoretical capacity factor.

The theoretical capacity factor (SIGMA value) of a centrifuge is calculated based on the method described in "Solid Liquid Separation" Second Edition, 1981, by Ladislav Svarovsky, Butterworth-Heineman. The factor is calculated according to the following relationship between: number of discs (n), gravitational acceleration (g), angular velocity (ω), angle of discs with vertical feed tube (α), radius inner disc package (η) and the outer radius of the disc package (r2).

<formula> formula see original document page 14 </formula>

According to a particularly preferred embodiment, after removal of organic volatiles and hot cracking, the must is diluted before undergoing yeast fermentation. In the present method, the must is preferably diluted to a density in the range 10-35 0P, preferably to a density in the range 10-30 0P, before yeast fermentation. Typically, during dilution, the density of the must is reduced by at least 2 degrees Plato, preferably by at least 4 degrees Plato and more preferably by at least 6 degrees Plato. High-density fermentation, for example, density above 35 0P, is not practical, as yeast growth and yeast metabolism are impaired at such high densities. Must dilution may occur before and / or after sediment removal. Preferably, the must is diluted after the sediment has been removed.

Dilution of the wort is achieved by combining the wort with a lower density aqueous stream than said wort. It is to be understood that such a water stream may consist, for example, of tap water or mine water. It is also within the scope of the present invention to employ aqueous effluent which was obtained from a washing operation in the brewing process. In particular, it may be advantageous to combine the wort with an aqueous stream that is obtained from washing the yeast. The dilution of the wort is advantageously done by combining the still hot wort with water of a substantially lower temperature. This can be done continuously as well as discontinuously, the former being preferred. Typically, the wort from which the organic volatiles have been removed has a temperature above 50 ° C, preferably above 60 ° C, more preferably in the range 70-100 ° C, when diluted.

The diluted must thus obtained may be fermented in batches or continuously. According to a particularly preferred embodiment, the fermentation of the diluted wort is achieved in a continuous manner as follows: - feeding the diluted wort into a propagation vessel in which it is combined with a recirculated stream of yeast-containing waste and in which oxygen is supplied. to start yeast growth;

feeding the must of the propagation vessel into a sequence of one or more fermentation vessels in which the yeast is kept suspended;

feeding the fermented must into one or more separators to remove a residue containing yeast;

- recirculate part of the yeast-containing residue into the propagation vessel; and

- feed the rest of the fermented must in the subsequent processing steps.

Typically, the original density of the combined streams of diluted must and yeast-containing residue in the propagation vessel and one or more fermentation vessels is greater than 120 P. Preferably, said original density is in the range of 14-35 0P, more preferably in the range of 15-30 0P.

In order to ensure that must growth occurs in the preparation vessel at a desirable high rate, oxygen must be supplied. This can be done by ensuring that the propagation vessel contains an air-free top space that is in open connection with the surrounding atmosphere and by vigorously shaking the fermentation broth. Alternatively, oxygen or air may be introduced into the yeast-containing must that is contained in the propagation vessel or may be introduced into the must or recirculated stream of yeast-containing waste before entering the propagation vessel. In either case, air or oxygen is advantageously distributed throughout the yeast-containing wort. This may be accomplished by stirring, recirculating and / or introducing oxygen or air through a plurality of gas injectors. According to a particularly preferred embodiment, oxygen is supplied by introducing it into the must stream before entering the propagation vessel. This mode offers the advantage that oxygen concentration can be precisely controlled. Oxygen is typically introduced into yeast-containing must in an amount of at least 8 ppm, preferably in an amount of 10-40 ppm, calculated in the main must current.

Typically, the residence time in the propagation vessel is in the range 0.5-5 hours. The residence time in the propagation vessel can be calculated by dividing the operating volume of the propagation vessel by the must flow towards the process. The operating volume of the propagation vessel is equal to the total volume of liquid contained in the vessel.

The recirculation of the yeast-containing residue in combination with oxygen supply makes it possible to maintain high yeast concentrations in the propagation vessel. Typically, the yeast content in the must in the propagation vessel is maintained at more than 20 g / liter (based on wet yeast). According to a particularly preferred embodiment, the must concentration of yeast in the propagation vessel is in the range of 30-300 g / L (again based on wet yeast). Even more preferably, the must yeast concentration in the propagation vessels is in the range of 50-200 g / l. The amount of wet yeast contained in a suspension is equal to the amount of yeast cake with a 73% water content that can be isolated from the suspension by centrifugation. The above water content includes the water contained in the yeast cells. Advantageously, these yeast concentrations are maintained in one or more fermentation vessels downstream of the propagation vessel. Using high concentration of yeast offers several important advantages, especially in terms of productivity and cost efficiency.

The present process can be operated at high efficiency by recirculating a large fraction of the yeast-containing residue that is obtained from the separation vessel. According to a preferred embodiment, between 10 and 100%, more preferably between 50 and 100% of the yeast pellet that is removed from the propagation vessel is recirculated for fermentation.

Typically, at least 20%, especially at least 40% of the yeast present in the fermented liquid is recirculated to the propagation vessel. More preferably at least 60% of the yeast present in the fermented liquid is recirculated, above all preferably at least 75% of the yeast present in the fermented liquid is recirculated. Normally no more than 98% of the yeast present in the fermented liquid is recirculated.

The temperature of the liquid in the propagation vessel is conveniently maintained in the range 5-40 ° C, preferably in the range 6-25 ° C, more preferably in the range 8-18 ° C. The propagation vessel can be operated at superatmospheric pressure, especially if pressurized air or oxygen is introduced into the vessel. Preferably, the propagation vessel is operated at approximately atmospheric pressure.

In order to maximize efficiency, it should be ensured that the part of the yeast-containing waste that is not recirculated to the propagation vessel has been largely exhausted in which virtually all (green) beer has been removed from it. This can be advantageously achieved by washing the yeast contained in the fermented mash and / or the unrecirculated yeast-containing residue.

Typically, at least 20%, especially at least 40% of the yeast present in the fermented must is removed from the fermented must before it is clarified or, if not clarified, before it is filled. Preferably at least 60%, more preferably at least 80%, even more preferably at least 90% and most preferably at least 95% of the yeast present in the fermented mash is removed. Preferably, the yeast is removed by sedimentation. The present method uses one or more fermentation vessels in which the yeast is kept suspended. Preferably, said yeast is not immobilized on a vehicle. The yeast is conveniently suspended in the fermentation vessels by stirring, recirculating and / or evolving carbon dioxide.

Typically, the combined residence time in one or more fermentation vessels is in the range of 5-80 hours.

The combined residence time in one or more fermentation vessels may be calculated by increasing the residence time in each of the fermentation vessels. The residence time in the fermentation vessel is calculated by dividing the total operating volume of the fermentation vessel by the must flow in the system.

The temperature of the fermenting wort in one or more fermentation vessels is conveniently maintained in the range of 5-40 ° C, preferably in the range of 6-25 ° C, more preferably in the range of 8-18 ° C. According to a particularly preferred embodiment, the present method employs at least two fermentation vessels. The use of two or more fermentation vessels offers the advantage that higher substrate conversion rates can be achieved in vessels prior to the last fermentation vessel. Typically, a sequence of more than 4 fermentation vessels is employed. More preferably, the method employs a sequence of 2 or 3 fermentation vessels.

In the present method, the combined residence time in the propagation vessel and one or more fermentation vessels typically does not exceed 80 hours. According to a preferred embodiment, said combined dwell time does not exceed 60 hours, more preferably, the combined dwell time is in the range of 10-50 hours. Such relatively short residence times may conveniently be achieved by employing relatively high yeast concentrations described hereinbefore.

Fermentation of diluted mash can be achieved in a batch manner as follows:

• feed the diluted must in a tank or feed the undiluted must in a tank and dilute it with water;

• inoculate the must with sufficient biologically active yeast; and

• ferment the wort to the desired final attenuation. Oxygen required for yeast propagation may be provided by introducing oxygen or air into the must-containing tank, or by introducing oxygen or air into the diluted or undiluted must prior to its introduction into the tank.

After removal of the yeast-containing residue from the fermented mash, the green beer thus obtained may be further processed. In the case of brewing, further processing preferably includes maturation, cold storage, clarification, carbonation and filling. Preferably, this further processing is also done on a continuous basis.

Typically, the present method employs a maturation step after removal of yeast cells from the fermentate. After fermentation, many undesirable flavors and aromas are present in "green" or immature beer. Maturation (also sometimes referred to as ripening) reduces the levels of these undesirable compounds to give a more palatable product. Preferably, the maturation step occurs in the present process prior to filtration, more preferably prior to processing in one or more separators. Advantageously, maturation is achieved in the present method in a continuous manner by feeding unripened beer into the upper part of the vessel. The beer moves down and the yeast settles through the volume of beer. The yeast is collected at the base of the vessel and above the yeast level the aged beer is removed and fed into cold storage vessels or cooled in the same vessel in which maturation was achieved. Beer remains at a low temperature for a period of time to allow coagulation and stabilization of colloidal particles.

Maturation can also be achieved in a batch process by maturing the immature beer in a maturation vessel or in a fermenter. After maturation, yeast is preferably removed. The beer is then transferred to cold storage tanks for stabilization, or cooled in the fermenter or maturation vessel.

Cold storage typically involves keeping the fermentate at a temperature of less than 10 ° C, preferably less than .5 ° C, more preferably less than 2 ° C for at least 12 hours, preferably at least 24 hours. According to a preferred embodiment, said cold storage is applied after maturation and before filtration.

According to a particularly advantageous embodiment of the method hereinbefore defined, said method is operated in a completely continuous manner. Continuous operation of this method offers numerous significant advantages, including:

• Higher productivity and less investment: vessels can be operated for extended periods under full load, meaning that for the same production volume smaller vessels are required than in a batch process;

• Constant and better quality: the process is easier to control because of the possibility of adapting process parameters to local and instantaneous requirements and, because of steady state conditions, are much more stable;

• high hygienic standard: the continuous process is operated in a closed system;

• less energy: energy consumption is evenly dispersed without major spikes in use;

• less labor: continuous process operation requires less attention;

• Less downtime and cleaning: The continuous process can be operated for much longer periods than batch processes.

Another aspect of the invention relates to an apparatus for producing a ground malt extract comprising:

- heating unit (3) having an output connected to one:

- sieving device (4) for receiving the suspension of the ground malt, the sieving device having a low solids outlet (5a) and a high solids outlet (6) for a stream comprising between 8% by weight and 25%. solids by weight connected to a pressing unit (7), the pressing unit (7) having a low solids output (5b) and a high solids output (8) for a stream comprising between 18% by weight and 40%. wt% solids;

- a mixing unit (2) having an inlet for an aqueous liquid and an inlet for a solid material, said mixing unit (2) having an outlet connected to the heating unit (3) and wherein the pressing unit ( 7) has a high solids outlet (8) connected to a mixing unit (9), whose mixing unit (9) also comprises an inlet (10) for an aqueous liquid, said mixing unit having an outlet that is connected to a second screening device (11), which has its high solids output (13) connected to a second pressing unit (14) and wherein the low solids output (12a) of the second screening device (11) and / or the low solids output (12b) of the second pressing unit (14) is connected to the input of the mixing unit (2). Also another aspect of the invention relates to an apparatus for producing a ground malt extract comprising:

- a heating unit (3) which has an output connected to:

- a sieving device (4) for receiving a wort suspension, the sieving device having a low solids outlet (5a) and a high solids outlet (6) for a stream comprising between 8% by weight and 25%. solids by weight connected to a mixing unit (22), whose mixing unit (22) also comprises an inlet (23) for an aqueous liquid, said mixing unit (22) having an outlet that is connected to a device (24) having a low solids output (5c) which has its high solids output (25) connected to:

- pressing unit (7), the pressing unit (7) having a low solids outlet (5b) and a high solids outlet (8) for a stream comprising between 18 wt% and 40 wt% solids.

According to a preferred embodiment, the latter apparatus comprises a mixing unit (2) having an inlet for an aqueous liquid and an inlet for a solid material, said mixing unit (2) having an outlet connected to the heating unit. (3) and wherein the pressing unit (7) has the high solids outlet (8) connected to a mixing unit (9), whose mixing unit (9) also comprises an inlet (10) for an aqueous liquid. said mixing unit having an outlet which is connected to a second screening device (11) which has its high solids outlet (13) connected to a second pressing unit (14) and wherein the low solids outlet (12a) of the second screening device (11) and / or the low solids output (12b) of the second pressing unit (14) is connected to the input of the mixing unit (2).

In a preferred embodiment, the screening device (4) comprises a vibrating screening surface. In a particularly preferred embodiment, the vibrating screening surface comprises a screen or mesh, a vibrating element being adapted to oscillate against a downstream side of the screening surface. The screening device (4) advantageously has a pore size between 20 μηι and 1 mm, preferably between 20 μηι and 300 μηι.

According to another advantageous embodiment of the present apparatus, the high solids outlet (16) of the second pressing unit (14) is connected to a third mixing unit (17) whose mixing unit (17) also comprises an inlet ( 10) for an aqueous liquid, said mixing unit having an outlet that is connected to a third screening device (18), which has its high solids outlet (20) connected to a third pressing unit (21) and at that the low solids output (19a) of the third screening device (18) and / or the low solids output (10b) of the third pressing unit (21) is connected to the input of the mixing unit (9).

In the arrangement of the apparatus shown in Figure 1, ground malt is continuously fed from the hopper 1 into the mixing vessel 2, in which the ground malt is thoroughly mixed with the recirculated aqueous stream 12 to produce a ground malt. The ground malt is continuously transferred from the mixing vessel 2 to the maceration tower 3 in which the ground malt is subjected to a heating regime that favors the enzymatic degradation of starch. The heat treated ground malt is fed from the maceration tower 3 to a first vibrating screen 4 where it is separated into the ground malt extract 5a and wet spent grain 6. The wet spent grain 6 is continuously transferred to the first screw press 7, wherein additional milled malt extract 5b is removed and dehydrated spent grain 8 is expressed. Ground malt extracts 5a and 5b are combined into a single stream of ground malt extract 5 before further processing. Dehydrated spent grain 8 obtained from the first screw press 7 is fed into a mixing vessel 9 where it is completely mixed with sprinkling water 10. The resulting suspension is continuously transferred to a second vibrating screen 11, where it is separated into water. Washed grain 12a and washed spent grain 13. The washed spent grain 13 is continuously transferred to the second screw press 14, in which rest water 12b is removed and the spent grain residue 15 is expressed. Wash water 12a and rest water 12b are combined into a single aqueous stream 12 which is recirculated to mixing vessel 2.

In the apparatus arrangement shown in Figure 2, ground malt is continuously fed from the hopper 1 into the mixing vessel 2, in which the ground malt is completely mixed with the recirculated aqueous stream 12 to produce a ground malt. The ground malt is continuously transferred from the mixing vessel 2 to the maceration tower 3 in which the ground malt is subjected to a heating regime that favors the enzymatic degradation of starch. The heat treated ground malt is fed from the maceration tower 3 to a first vibrating screen 4 where it is separated into ground malt extract 5a and wet spent grain 6. Wet spent grain 6 is continuously transferred to the first screw press 7, wherein additional milled malt extract 5b is removed and dehydrated spent grain 8 is expressed. Ground malt extracts 5a and 5b are combined into a single stream of ground malt extract 5 before further processing. Dehydrated spent grain 8 obtained from the first screw press 7 is fed into a mixing vessel 9 where it is thoroughly mixed with a recirculated aqueous stream 19. The resulting suspension is continuously transferred to a second vibrating screen 11, where it is separated into the wash water 12a and washed spent grain 13. Washed spent grain .13 is continuously transferred to the second screw press 14, in which additional resting water 12b is removed and spent grain residue 16 is expressed. Wash water 12a and rest water 12b are combined into a single aqueous stream 12 which is recirculated to mixing vessel 2. The spent grain residue 16 is transferred to a mixing vessel 17 where it is thoroughly mixed with sprinkling water 10. The resulting suspension is continuously transferred from mixing vessel 17 to a third vibrating screen 18, where it is separated into diluted wash water 19a and extracted spent grain 20. Extracted spent grain 20 is continuously transferred to a third screw press 21, in which diluted resting water 19b is removed and spent spent grain 15 is expressed. Diluted wash water 19a and dilute resting water 19b are combined into an aqueous stream 19 which is recirculated to mixing vessel 9.

In the apparatus arrangement shown in Figure 3, ground malt is continuously fed from the hopper 1 into the mixing vessel 2, in which the ground malt is thoroughly mixed with the recirculated aqueous stream 12 to produce a ground malt. The ground malt is continuously transferred from the mixing vessel 2 to the maceration tower 3 in which the ground malt is subjected to a heating regime that favors the enzymatic degradation of starch. The heat treated ground malt is fed from the maceration tower 3 to a first vibrating screen 4 where it is separated into wet ground malt extract 5a and wet spent grain 6. The wet spent grain 6 is continuously transferred to a mixing vessel 22 where it is completely mixed with sprinkler water 23. The resulting suspension is continuously transferred to a second vibrating screen 24 where it is separated into wash water 5c and wet spent grain 25. Wet spent grain .25 is continuously transferred to the first press 7, in which additional ground malt extract 5b is removed and dehydrated spent grain 8 is expressed. Ground malt extracts 5a, 5b and wash water 5c are combined into a single stream of ground malt extract 5 before further processing. Dehydrated spent grain 8 obtained from the first screw press 7 is fed into a mixing vessel 9 where it is completely mixed with sprinkling water 10. The resulting suspension is continuously transferred to a third vibrating screen 11, where it is separated into water. wash 12a and wet spent grain 13. Wet spent grain 13 is continuously transferred to the second screw press 14, in which resting water 12b is removed and spent grain residue 15 is expressed. Wash water 12a and rest water 12b are combined into a single aqueous stream 12 which is recirculated to mixing vessel 2.

The invention is illustrated in more detail by the following examples.

EXAMPLES

Example 1:

A stream of 960 kg / h of must must be produced with an extract concentration of 140 P at the end of the must production process. This must is fermented, matured and stabilized in batch fermenters and subsequently continuously centrifuged and filtered.

At the front of the process 455 L / h of infusion water (50 ° C) is continuously mixed with 205 kg / h of ground pestle malt grain (sieve size 1.5 mm). Both streams are fed into a 70 liter working volume continuously stirred tank reactor at a temperature of 58 ° C. The residence time of this treatment is about 7 minutes and serves for the usual breakdown of proteins in malt and allows the dissolution and degradation of glucans and related components.

Then the mixture, referred to as "ground malt", is fed into a piston flow vertical tubular reactor. This type of reactor has been described in prior Heineken patents (WO 92/12231). At certain times in the column, ground malt is heated by direct steam injection and the entire reactor is insulated to minimize heat loss. Temperatures are chosen such that the conversion of malt starch to fermentable sugars is appropriate for the desired product. The temperature profile in this example has a first rest at 58 ° C to 13. The subsequent resting saccharification at 67 ° C lasts 80 minutes and the ground malt is then heated to a ground malt removal temperature of 78 ° C. C, at whose temperature there is a final rest of 7 minutes. Ground malt has a total residence time in the column of 100 minutes, and the resulting ground malt is fed into the ground malt separation section. Prior to separation of ground malt, ground malt is diluted to an extract concentration of 13.7 ± 1.0 0P (95% Cl) by the addition of hot water at 78 ° C. Separation of malt shells and other solids from ground malt is made by a VTS 1200 type vibrating screen provided by Allgaier Werke GmbH, Uhingen, Germany. This sieve is operated with a 100 μηι stainless steel cloth filter. Underneath the cloth filter, polymeric spheres collide with the cloth to prevent soot formation and clogging of the cloth filter pores. The sieve separates the particles in the ground malt into a stream of 24% fines and 76% coarse materials. The fines are suspended in a stream of liquid that passes through the pores of the sieve cloth at a flow rate of 1,002 ± 15 L / h. The coarse particles are thickened to a dry matter concentration of 15.8 ± 2.3% (w / w) and still contain a significant amount of extract and water. This retained spent grain liquid content is subsequently reduced by feeding partially dehydrated coarse material into a filter press equipped with a 150 μιη dehydration section at a flow rate of 193 ± 7 kg / h. A significant amount of liquid is thus removed from the spent grain (41 ± 1.4 25 kg / h) and the final dry matter concentration in the discharged spent grain is 21.2 ± 3.8% (w / w). The overall extract loss is 14.4%.

The ground malt separation product is now referred to as must, and has a flow rate of approximately 1,000 L / h. Hop extract at a rate of 7 g / h is dosed continuously in-line and the mixture is heated to a temperature of 103 ° C by a steam-fed heat exchanger. The must is pumped into a piston flow vertical tubular reactor. This column reactor has the same dimensions as the maceration conversion column previously described and the residence time is 60 minutes. Typical reactions that occur in this reactor are: protein denaturation and coagulation, sterilization, hop isomerization, color formation, dimethylsulfide (DMS) production from its malt-based precursor (S-methylmethionine).

The must is then treated in a sieve-plate geometry removal column previously described in Heineken patent (WO. 95/26395). 1.5 bar steam is used in countercurrent operation to remove undesirable flavor compounds (mainly DMS) at a flow rate of 20 kg / h and under atmospheric conditions at the top of the remover. The must that leaves the base of the remover is fed into a small temporary storage with negligible dimensions and directly fed into a continuous discharge type centrifuge. This machine has a rotational speed of 7,400 and a theoretical capacity factor of 13,000 m2.

Next, wort cooling takes place in two plate or parallel-frame wort coolers that reduce wort temperature from 95-100 ° C to 8 ° C by means of a two-stage water-glycol setting.

A total volume of 2.2 m3 of chilled must is continuously fed into a cylindrical / conical fermentation tank, along with active yeast at a concentration of 2.5 g / l. Continuous oxygenation is achieved by inline aeration. The primary batch fermentation was performed at 10 ° C and, when the extract concentration reached 6.5 0P, the temperature was naturally increased to 13 ° C. After diacetyl concentrations were reduced to a level of 30 ppm, the tank contents were cooled to -1.5 ° C within 24 hours. This cold phase was maintained for 6 days.

The beer was then filtered over a vertical disc-type kieselguhr light beer filter. After this filtration, the beer was stabilized with the usual dosages of PVPP (polyvinylpyrrolidone) and the necessary PVPP filtration. Finally, the beer was packaged in suitable containers (glass bottle).

Example 2

A stream of 905 kg / h of must must be produced with an extract concentration of 16,50P at the end of the must production process. This must is fermented, matured and stabilized in batch fermenters and subsequently continuously centrifuged and filtered.

At the front of the process, 460 L / h of infusion water (50 ° C) is continuously mixed with 206 kg / h of ground malt grain in a hammer mill (sieve size 1.5 mm). Both streams are fed into a 70 liter working volume continuous agitation tank reactor at a temperature of 58 ° C. The residence time of this treatment is about 7 minutes and serves for the usual breakdown of proteins in malt and allows the dissolution and degradation of glucans and related components.

Then the mixture, referred to as "ground malt", is fed into a piston flow vertical tubular reactor. This type of reactor has been described in prior patents by Heineken (WO 92/12231). At certain times in the column, the ground malt is heated by direct steam injection and the reactor is completely insulated to minimize heat loss. Temperatures are chosen such that the conversion of malt starch to fermentable sugars is appropriate for the desired product. The temperature profile in this example has a first rest at 58 ° C to 13. The subsequent saccharification rest at 67 ° C has a duration of 80 minutes and the ground malt is then heated to a melting temperature of 78 ° C in whose temperature there is a final rest of 7 minutes. Ground malt has a total residence time within the column of 100 minutes and the resulting ground malt is fed into the ground malt separation section.

Separation of malt shells and other ground malt solids is by a VTs 1200 type vibrating screen provided by Allgaier Werke GbmH, Uhingen, Germany. This sieve is operated with a 100 μηι stainless steel cloth filter. Underneath the sieve cloth, polymeric balls collide with the cloth to prevent soot formation and clogging of the pores of the sieve cloth. Underneath the sieve cloth, polymeric balls collide with the cloth to prevent soot formation and clogging of the pores of the sieve cloth. The sieve separates the particles in the ground malt into a stream of 24% fines and 76% coarse materials. The fines are suspended in a stream of liquid that passes through the pores of the sieve cloth at a flow rate of 970 L / h. The coarse particles are thickened to a dry matter concentration of 16% (w / w) and fed into a mixing tank where the extract concentration is reduced by the addition of a 510 L / h stream of 78 ° C infusion water. Ç. The product of this mixing tank is again separated by a vibrating screen (VTS 600) with a 100 μηι cloth. The coarse spent grain fraction still contains a significant amount of extract and water. This liquid content of the retained spent grain is subsequently reduced by feeding partially dehydrated coarse material into a screw press equipped with a 150 μιτι dehydration section at a flow rate of 205 kg / h. A significant amount of liquid is thus removed from the spent grain and the final dry matter concentration in the discharged spent grain is 24% (w / w). The second sieve liquid product is recirculated and mixed with the ground malt stream to obtain a diluted feed stream in the first sieve, thereby optimizing extract recovery conditions. The overall extract loss is therefore reduced to 2.6% on separation of ground malt. The ground malt separation product is now referred to as a must and has a flow rate of 970 L / h. Hop extract at a rate of 7 g / h is dosed continuously in-line and the mixture is heated to a temperature of 10 0 ° C by a steam-fed heat exchanger. The must is pumped into a piston flow vertical tubular reactor. This column reactor has the same dimensions as the maceration conversion column previously described and the residence time is 65 minutes. Typical reactions that occur in this reactor are: protein denaturation and coagulation, sterilization, hop isomerization, color formation, dimethyl sulfide (DMS) production from its malt-based precursor (S-methylmethionine).

The must is then treated in a sieve - plate geometry removal column previously described in Heineken patent (WO 95/26395). Steam at 1.5 bar is used in countercurrent operation to remove unwanted flavor compounds (mainly DMS) at a flow rate of 20 kg / h and under atmospheric conditions at the top of the remover. The must that leaves the base of the remover is fed into a small temporary storage with negligible dimensions and directly fed into a discontinuous discharge type centrifuge. This machine has a rotational speed of 7,400 rpm and a theoretical capacity factor of 13,000 m. The discharge frequency is regulated by the cake deposit inside the machine.

Next, wort cooling occurs in two parallel plate and frame wort coolers that reduce wort temperature from 95 -100 ° C to 8 ° C by the two-stage water-glycol setting.

The total volume of 2.2 m3 of brake must is continuously fed into a cylindrical / conical fermentation tank along with active yeast at a concentration of 2.5 g / L. Continuous oxygenation is achieved by inline aeration. Fermentation of the primary batch was carried out at 10 ° C and, when the extract concentration reached 6.5 0P, the temperature naturally increased to 13 ° C. After the diacetyl concentration was reduced to a level of 30 ppm, the tank contents were cooled to -1.50C within 24 hours. This cold phase was maintained for 6 days.

The beer was then filtered through a vertical disc-type kieselguhr light beer filter. After this filtration, the beer was stabilized with usual PVPP dosages and the necessary PVPP filtration. Finally, the beer was packed in suitable containers (glass bottle).

Example 3

A stream of 904 kg / h of must must be produced with an extract concentration of 16,50P at the end of the must production process. This must is fermented, matured and stabilized in batch fermenters and subsequently continuously centrifuged and filtered.

At the front of the process, 410 L / h of infusion water (50 ° C) is continuously mixed with 205 kg / h of ground malt grain in a hammer mill (sieve size 1.5 mm). Both streams are fed into a 70 liter working volume continuous agitation tank reactor at a temperature of 58 ° C. The residence time of this treatment is about 7 minutes and serves for the usual breakdown of proteins in malt and allows the dissolution and degradation of glucans and related components.

Then the mixture, referred to as "ground malt", is fed into a piston flow vertical tubular reactor. This type of reactor has been described in prior patents by Heineken (WO 92/12231). At certain times in the column, the ground malt is heated by direct steam injection and the reactor is completely insulated to minimize heat loss. Temperatures are chosen such that the conversion of malt starch to fermentable sugars is appropriate for the desired product. The temperature profile in this example has a first rest at 58 ° C to 13. The subsequent saccharification rest at 67 ° C has a duration of 80 minutes and the ground malt is then heated to a melting temperature of 78 ° C and the The ground malt is then heated to a quenching temperature of 78 ° C, at which temperature there is a final rest of 7 minutes. Ground malt has a total residence time within the column of 100 minutes and the resulting ground malt is fed into the ground malt separation section.

Separation of malt shells and other ground malt solids is by a VTS 1200 type vibrating screen provided by Allgaier Werke GbmH, Uhingen, Germany. This sieve is operated with a 100 μηι stainless steel cloth filter. Underneath the sieve cloth, polymeric balls collide with the cloth to prevent soot formation and clogging of the pores of the sieve cloth. The sieve separates the particles in the ground malt into a stream of 24% fines and 76% coarse materials. The fines are suspended in a stream of liquid that passes through the pores of the sieve cloth at a flow rate of 971 L / h. The coarse particles are thickened to a dry matter concentration of 16% (w / w) and fed into a screw press where the dry matter content of the spent grain increased to 21%. The resulting liquid is recirculated to the aforementioned sieve while spent grain is fed into a tank where the extract concentration is reduced by the addition of a 540 L / h stream of infusion water at 78 ° C. The product of this mixing tank is again separated by a vibrating screen (VTS 600) with a 100 μηι cloth. The coarse spent grain fraction still contains a significant amount of extract and water. This liquid content of the retained spent grain is subsequently reduced by feeding partially dehydrated coarse material into a screw press equipped with a 150 μπι dehydration section at a flow rate of 205 kg / h. A significant amount of liquid is thus removed from the spent grain and the final dry matter concentration in the discharged spent grain is 28% (w / w). The second sieve liquid product is recirculated and mixed with the ground malt stream to obtain a diluted feed stream in the first sieve, thereby optimizing extract recovery conditions. The overall extract loss is therefore reduced to .1.5% on separation of ground malt.

The ground malt separation product is now referred to as a must and has a flow rate of 971 L / h. Hop extract at a rate of 7 g / h is dosed continuously in-line and the mixture is heated to a temperature of 10 0 ° C by a steam-fed heat exchanger. Then must is pumped into a piston flow reactor. This column reactor has the same dimensions as the maceration conversion column previously described and the residence time is 65 minutes. Typical reactions that occur in this reactor are: protein denaturation and coagulation, sterilization, hop isomerization, color formation, dimethyl sulfide (DMS) production from its malt-based precursor (S-methylmethionine).

The must is then treated in a sieve - plate geometry removal column previously described in Heineken patent (WO 95/26395). Steam at 1.5 bar is used in countercurrent operation to remove unwanted flavor compounds (mainly DMS) at a flow rate of 20 kg / h and under atmospheric conditions at the top of the remover. The must that leaves the base of the remover is fed into a small temporary storage with negligible dimensions and directly fed into a discontinuous discharge type centrifuge. This machine has a rotational speed of 7,400 rpm and a theoretical capacity factor of 13,000 m. The discharge frequency is regulated by the cake deposit inside the machine.

Next, wort cooling occurs in two parallel plate and frame wort coolers that reduce wort temperature from 95 -100 ° C to 8 ° C by the two-stage water-glycol setting.

The total volume of 2.2 m3 of cold must is continuously fed into a cylindrical / conical fermentation tank along with active yeast at a concentration of 2.5 g / L. Continuous oxygenation is achieved by inline aeration. Fermentation of the primary batch was carried out at 10 ° C and, when the extract concentration reached 6.5 0P, the temperature naturally increased to 13 ° C. After the diacetyl concentration was reduced to a level of 30 ppm, the tank contents were cooled to -1.5 ° C within 24 hours. This cold phase was maintained for 6 days.

The beer was then filtered through a vertical disc-type kieselguhr light beer filter. After this filtration, the beer was stabilized with usual PVPP dosages and the necessary PVPP filtration. Finally, the beer was packed in suitable containers (glass bottle).

Claims (23)

Method for producing a ground malt extract, characterized in that it comprises: a. macerate starch-containing particulate raw materials and optionally malted with water; B. heat the ground malt and enzymatically hydrolyze the starch; ç. passing the heat-treated ground malt in a first sieve for separation into a fermentable ground malt extract and wet spent grain; and d. transferring the wet spent grain, optionally after the wet spent grain has been subjected to a washing and screening operation, to a first press and pressing said wet spent grain to obtain spent water grain removed and additional fermentable ground malt extract. Method according to claim 1, characterized in that it comprises the additional steps of: e. transferring the spent grain with removed water to a first mixing vessel and mixing it with sprinkling water to produce a suspension; f. passing the suspension through a second sieve to separate washed spent grain and wash water; and g. transferring the washed spent grain to a second press and pressing said washed spent grain to obtain spent grain residue and resting water. Method according to claim 1 or 2, characterized in that, prior to being transferred to the first press, the wet spent grain is subjected to a washing and sieving operation comprising: • transferring the wet spent grain to a washing vessel and mix it with sprinkling water to produce a suspension; • pass the suspension through an additional sieve for separation of wet spent grain and wash water. Method according to claim 2 or 3, characterized in that at least a part of the wash water and / or rest water is recirculated to the maceration step a) and / or combined with the heat-treated ground malt. before he goes through the first sieve. Method according to any one of claims 2-4, characterized in that both the wash and the rest water are completely recirculated. Method according to any one of claims 2-5, characterized in that the washing water and / or the resting water are recirculated to the maceration step a). A method according to any one of claims 2-6, characterized in that the total amount of recirculated wash water and rest water constitutes at least 80% by weight, preferably at least 90% by weight of the total amount. water used in the maceration stage. Method according to any one of the preceding claims, characterized in that the density of the fermentable ground malt extract obtained from the first separator exceeds 150 P. Method according to any one of claims 2-8, characterized in that steps c) to g) are carried out continuously. Method according to any one of the preceding claims, characterized in that the sieves are vibrating sieves. Method according to any one of the preceding claims, characterized in that the presses are screw presses. A method according to any one of claims 2-11, characterized in that it comprises: h. transferring the spent grain residue obtained from the second press to a second mixing vessel and mixing it with sprinkling water to produce a suspension; i. passing the suspension through a third sieve to separate extracted spent grain and diluted wash water; j. transferring the extracted spent grain to a third press and pressing said extracted spent grain to obtain exhausted spent grain residue and dilute resting water; and k. recirculate at least a portion of the diluted wash water and / or dilute resting water to the first mixing vessel. Method according to any one of the preceding claims, characterized in that the loss of extract observed in the production of ground malt extract is less than 15 wt%, preferably less than 3 wt%. A method according to any one of the preceding claims, characterized in that it comprises the additional steps of: • converting the optionally hopped macerated extract to wort by heating said ground malt extract to a temperature of at least 60 ° C per minus 15 minutes; • remove organic volatiles from hot must by reducing the pressure and / or by removing them with a gas or steam; wherein the density of the ground malt extract is maintained at .150P or more, preferably at 180P or more, more preferably at 20P or more during these additional steps. A method according to claim 14, characterized in that after removal of organic volatiles, the must is diluted to a density in the range 10-25 0P prior to yeast fermentation. Method according to any one of the preceding claims, characterized in that said method is operated in a totally continuous manner. 17. Apparatus for producing a ground malt extract, characterized in that it comprises: - a heating unit (3) having an outlet connected to: - a sieving device (4) for receiving a ground malt suspension; sieving device having a low solids output (5a) and a high solids output (6) for a stream comprising between 8 wt% and 25 wt% solids connected to a press unit (7) the pressing unit (7) having a low solids outlet (5b) and a high solids outlet (8) for a stream comprising between 18 wt% and 40 wt% solids; - a mixing unit (2) with an inlet for an aqueous liquid and an inlet for a solid material, said mixing unit (2) having an outlet connected to the heating unit (3) and wherein the pressing unit ( 7) has the high solids outlet (8) connected to a mixing unit (9), whose mixing unit (9) also comprises an inlet (10) for an aqueous liquid, said mixing unit having an outlet which is connected to a second screening device (11), which has its high solids output (13) connected to a second pressing unit (14) and wherein the low solids output (12a) of the second sieving device (11) and / or the low solids outlet (12b) of the second pressing unit (14) is connected to the inlet of the mixing unit (2). 18. Apparatus for producing a ground malt extract, characterized in that it comprises: - a heating unit (3) having an outlet connected to: - a sieving device (4) for receiving a ground malt suspension, the screening device having a low solids output (5a) and a high solids output (6) for a stream comprising between 8 wt% and 25 wt% solids connected to a mixing unit (22). ), whose mixing unit (22) also comprises an inlet (23) for an aqueous liquid, said mixing unit (22) having an outlet that is connected to a screening device (24) having a low content outlet. solids (5c) having a high solids output (25) connected to: - pressing unit (7), pressing unit (7) having a low solids output (5b) and an output solids (8) for a stream comprising between 18% by weight and 40% by weight. solids weight. Apparatus according to claim 18, characterized in that it comprises a mixing unit (2) having an inlet for an aqueous liquid and an inlet for a solid material, said mixing unit (2) having an outlet connected to the heating unit (3) and wherein the pressing unit (7) has the high solids output (8) connected to a mixing unit (9), whose mixing unit (9) also comprises an inlet. (10) for an aqueous liquid, said mixing unit having an outlet which is connected to a second screening device (11), which has its high solids outlet (13) connected to a second pressing unit (14). ) and wherein the low solids outlet (12a) of the second screening device (11) and / or the low solids outlet (12b) of the second pressing unit (14) is connected to the inlet of the second screening unit (14). mixture (2). Apparatus according to any of claims 17-19, characterized in that the sieving device (4) comprises a vibrating sieving surface. Apparatus according to claim 20, characterized in that the vibrating screening surface comprises a sieve or mesh, a vibrating element being adapted to oscillate against a downstream side of the screening surface. Apparatus according to any one of claims. 17-21, characterized in that the screening device has a pore size of between 20 μιτι and 1 mm, preferably between 20 μπι and 300 μιτι. Apparatus according to claim 17 or 19, characterized in that the high solids outlet (16) of the second pressing unit (14) is connected to a third mixing unit (17), the unit of which The mixture (17) also comprises an inlet (10) for an aqueous liquid, said mixing unit having an outlet that is connected to a third screening device (18), which has its high solids outlet (20) connected. to a third pressing unit (21) and wherein the low solids outlet (19a) of the third screening device (18) and / or the low solids outlet (19b) of the third pressing unit (21) ) is connected to the input of the mixing unit (9).